Ground source/water source heat exchange heating/cooling systems typically utilized closed loops of tubing buried in the ground or placed in water, such as a lake. These closed loops may be installed in a variety of manners, including horizontal configurations or helical loops, as well as in vertical configurations typically consisting of elongated U-shaped tubes placed into holes drilled into the earth. These heat exchange loops may carry a water/anti-freeze mixture in a water source system, or a refrigerant in a direct exchange system.
While all such ground source heat exchange designs work relatively well, there are four common disadvantages. The first is that either extensive excavation or expensive well drilling is necessary. The second is that achieving good compaction and heat transfer in the excavated ground is difficult and expensive, often requiring detailed and extensive grouting when wells are employed. The third disadvantage, particularly common in closed loop well installations, is that the water or refrigerant or other heat exchange fluid, once it has either acquired or rejected heat as it travels deep into the well, must return in close proximity to the opposite respective cold or hot entering tube, which imposes a negative impact on the most efficient heat exchange achieved during the heat exchange fluid's deepest geothermal or submersion transit. The fourth disadvantage is that the contact surface area of the tubes carrying the heat exchange fluid is typically rather small, especially in direct expansion systems.
While various designs, such as that disclosed by U.S. Pat. No. 5,261,251 [Galiyano] and U.S. Pat. No. 5,054,541 [Tripp], help reduce land area requirements, they still require excavation and are still subject to the other disadvantages noted above.
Consequently, it is an object of the present invention to provide a geothermal heat exchange unit, which can be placed in ground or in water, which is relatively inexpensive to install, without the need for extensive excavation, and which instantly achieves good ground compaction without the necessity of grouting or other special fill.
It is also an object of the present invention to insulate the returning heat exchange tube from the adverse thermal effects of the entering heat exchange tube which, in turn, significantly increases the surface area of heat exchange contact with the natural surrounding earth or water without adverse heating or cooling effects between the tubes.
Further, the present invention provides a relatively inexpensive and efficient means of primarily providing and/or of supplementing the heating/cooling work accomplished via any heating/cooling system, such as a hydronic or an air-to-air heat pump system.